Figure 1.

Empirical density estimates of the t-statistics before and after quantile normalization. Empirical density estimates of the t-statistics before and after quantile normalization. Gene expression are simulated
by using normal random numbers with standard deviation 0.35 and gene-gene correlation
0.9. Total number of genes is m = 1000. Total numbers of truly differentially expressed genes are for up-regulated genes and m1- = 40 for down-regulated genes. The sample size is n = 10 and the true effect size is e+ = -e- = e = {0,2,4}. Estimates are based on 200 repetitions.